Read range measurements of UHF RFID transponders in mobile anechoic chamber

This paper presents a novel and simple method to determine the read ranges of radio frequency identification (RFID) transponders. Range tests in a well defined and accurate stationary anechoic chamber (SC) are awkward and expensive. An extendible mobile anechoic chamber (MC) to produce a large number of repeatable range measurements with minimal effort is proposed. A mobile chamber suitable to reside in our laboratories was designed and built. MC measurements were crosschecked with SC measurements of label transponders. Reading ranges for a number of commercially available metal mount tags, so far not publicly available, were derived. Metal transponders are 3D objects leading to more constraints in applications than labels. Therefore range densities, i.e. reading range per area or volume of the tag, as novel key figures were introduced to make tags more comparable and to determine the optimal transponder for a given use case. The current results are suitable to serve as a relative measure to compare transponders.